As the miniaturization of electric devices progresses, it is desirable to provide more compact electronic components, such as inductors, capacitors, and filters, for use in such electronic devices. To maintain electronic characteristics and to achieve further miniaturization of electronic components, a conductive filler is needed to have a smooth surface with no pinholes. And metal particles in the conductive composition are also advantageously reduced in size to result in higher dispersion. Aggregated metal particles and deformed metal particles in the conductive composition or paste that forms internal electrodes of ceramic multilayer components may cause electric defectives, such as short circuiting. Particularly, in thin-film, multilayer electronic components, it is beneficial for metal particles to be reduced in size for providing higher dispersion. When the particle size of the aggregated metal particles becomes larger than film thickness of the internal electrodes, ceramics between the internal electrodes are greatly stressed, resulting in a marked reduction in the reliability and a lower yield of the ceramic laminated component.
Conventionally, methods to disperse metal powders into a resin carrier and an organic solvent can include using equipment such as Laikai machine (a mixing and grinding machine), a triple roller or a ball mill, and a collision dispersion method which high pressure slurries collide among themselves. The collision dispersion method is disclosed in Japanese Patent Unexamined Publication 9-201521, Japanese Patent Unexamined Publication 9-299774, Japanese Patent Unexamined Publication 10-57789, PCT publication WO 00/04559, Japanese Patent Unexamined Publication 10-887457 and Japanese Patent Unexamined Publication 11-1460511.
However, the media used in the dispersion treating method, when the metal particles are submicron or less, or when the metal particles are firmly aggregated, suffers from a problem of not being able to make the metal particles ultra-fine and disperse the particles uniformly. A further drawback is excess action of media in deforming the metal particles.
Moreover, collision dispersion method, after a drying step, has its limit for firmly aggregated metal particles to be sufficiently crushed and to be uniformly dispersed. And to disperse the firmly aggregated metal particles to a certain extent, lengthy treatment is required along with an increase in required energy. Accordingly, poor efficiency and increased production costs result from such a method.